U.S. patent application number 13/508010 was filed with the patent office on 2012-09-06 for coated tool.
This patent application is currently assigned to Tungaloy Corporation. Invention is credited to Yohei Sone.
Application Number | 20120225247 13/508010 |
Document ID | / |
Family ID | 43970046 |
Filed Date | 2012-09-06 |
United States Patent
Application |
20120225247 |
Kind Code |
A1 |
Sone; Yohei |
September 6, 2012 |
Coated Tool
Abstract
A coated tool is excellent in adhesiveness of film, wear
resistance, crater resistance and chipping resistance. The coated
tool has a substrate and a coating coated on the surface thereof,
at least one layer of the coating being an .alpha.-type aluminum
oxide film, an average film thickness of the .alpha.-type aluminum
oxide film being about 0.5 to about 10 .mu.m, an average grain size
of the .alpha.-type aluminum oxide film being about 0.5 to about
1.5 .mu.m, and a texture coefficient TC.sub.A(012) of (012) plane
of the .alpha.-type aluminum oxide film and a texture coefficient
TC.sub.A(104) of (104) plane of the .alpha.-type aluminum oxide
film satisfying TC.sub.A(104)/TC.sub.A(012).gtoreq.2.0.
Inventors: |
Sone; Yohei; (Fukushima,
JP) |
Assignee: |
Tungaloy Corporation
Iwaki-shi, Fukushima
JP
|
Family ID: |
43970046 |
Appl. No.: |
13/508010 |
Filed: |
November 8, 2010 |
PCT Filed: |
November 8, 2010 |
PCT NO: |
PCT/JP2010/069791 |
371 Date: |
May 3, 2012 |
Current U.S.
Class: |
428/141 ;
428/216; 428/336 |
Current CPC
Class: |
Y10T 428/24355 20150115;
Y10T 428/24942 20150115; Y10T 407/27 20150115; Y10T 428/265
20150115; C23C 28/044 20130101; C23C 16/34 20130101; Y10T 428/24975
20150115; C23C 16/403 20130101; C23C 30/005 20130101 |
Class at
Publication: |
428/141 ;
428/336; 428/216 |
International
Class: |
B32B 3/00 20060101
B32B003/00; B32B 7/02 20060101 B32B007/02; B32B 5/00 20060101
B32B005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 6, 2009 |
JP |
2009-254703 |
Claims
1. A coated tool comprising a substrate and a coating provided on
the surface of the substrate, at least one layer of the coating
being an .alpha. type aluminum oxide film, an average film
thickness of the .alpha. type aluminum oxide film being about 0.5
to about 10 .mu.m, an average grain size of .alpha. type aluminum
oxide grains in the .alpha. type aluminum oxide film being about
0.5 to about 1.5 .mu.m, and a first texture coefficient
TC.sub.A(012) of a (012) plane of the .alpha.-type aluminum oxide
film and a second texture coefficient TC.sub.A(104) of a (104)
plane of the .alpha. type aluminum oxide film satisfy
TC.sub.A(104)/TC.sub.A(012).gtoreq.2.0, wherein: TC A ( 012 ) = I A
( 012 ) I A 0 ( 012 ) 1 8 [ I A ( 012 ) I A 0 ( 012 ) + I A ( 104 )
I A 0 ( 104 ) + I A ( 110 ) I A 0 ( 110 ) + I A ( 113 ) I A 0 ( 113
) + I A ( 024 ) I A 0 ( 024 ) + I A ( 116 ) I A 0 ( 116 ) + I A (
124 ) I A 0 ( 124 ) + I A ( 030 ) I A 0 ( 030 ) ] ; ##EQU00006## TC
A ( 104 ) = I A ( 104 ) I A 0 ( 104 ) 1 8 [ I A ( 012 ) I A 0 ( 012
) + I A ( 104 ) I A 0 ( 104 ) + I A ( 110 ) I A 0 ( 110 ) + I A (
113 ) I A 0 ( 113 ) + I A ( 024 ) I A 0 ( 024 ) + I A ( 116 ) I A 0
( 116 ) + I A ( 124 ) I A 0 ( 124 ) + I A ( 030 ) I A 0 ( 030 ) ] ;
##EQU00007## I.sub.A(hkl): X-ray diffraction intensity measured at
(hkl) plane of the .alpha.-type aluminum oxide film; I.sub.A0(hkl):
standard X-ray diffraction intensity of the (hkl) plane of
.alpha.-type aluminum oxide according to JCPDS card No. 10-173: and
(hkl) are eight planes of (012), (104), (110), (113), (024), (116),
(124) and (030).
2. The coated tool according to claim 1, wherein the .alpha.-type
aluminum oxide film is columnar crystal.
3. The coated tool according to claim 1, wherein the coating
comprises the .alpha.-type aluminum oxide film alone, or, a metal
compound film of one or more of a carbide, nitride, oxide,
carbonitride, carboxide, nitroxide, carbonitroxide and boride of
Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al and Si, and mutual solid
solutions thereof, and the .alpha.-type aluminum oxide film.
4. The coated tool according to claim 1, wherein
TC.sub.A(104)/TC.sub.A(012) is 4.0 or more.
5. The coated tool according to claim 1, wherein
TC.sub.A(104)/TC.sub.A(012) is 6.0 or more.
6. The coated tool according to claim 1, wherein a B1-type metal
compound film is present between the substrate and the .alpha.-type
aluminum oxide film, an average grain size of B1-type metal
compound grains in the B1-type metal compound film is about 0.15 to
about 0.3 .mu.m, a maximum grain size of the B1-type metal compound
grains in the B1-type metal compound film is about 1.0 .mu.m or
less, and a third texture coefficient TC.sub.B(422) of a (422)
plane of the B1-type metal compound film and a fourth texture
coefficient TC.sub.B(311) of a (311) plane of the B1-type metal
compound film satisfy TC.sub.B(422)/TC.sub.B(311).gtoreq.1.5,
wherein: TC B ( 422 ) = I B ( 422 ) I B 0 ( 422 ) 1 8 [ I B ( 111 )
I B 0 ( 111 ) + I B ( 220 ) I B 0 ( 220 ) + I B ( 200 ) I B 0 ( 200
) + I B ( 311 ) I B 0 ( 311 ) + I B ( 331 ) I B 0 ( 331 ) + I B (
420 ) I B 0 ( 420 ) + I B ( 422 ) I B 0 ( 422 ) + I B ( 511 ) I B 0
( 511 ) ] ; ##EQU00008## TC B ( 311 ) = I B ( 311 ) I B 0 ( 311 ) 1
8 [ I B ( 111 ) I B 0 ( 111 ) + I B ( 220 ) I B 0 ( 220 ) + I B (
200 ) I B 0 ( 200 ) + I B ( 311 ) I B 0 ( 311 ) + I B ( 331 ) I B 0
( 331 ) + I B ( 420 ) I B 0 ( 420 ) + I B ( 422 ) I B 0 ( 422 ) + I
B ( 511 ) I B 0 ( 511 ) ] ; ##EQU00009## I.sub.B(hkl): X-ray
diffraction intensity measured at (hkl) plane of the B1-type metal
compound film; I.sub.B0(hkl): average value of standard X-ray
diffraction intensity of a (hkl) plane of TiC according to JCPDS
card No. 32-1383 and standard X-ray diffraction intensity of a
(hkl) plane of TiN according to JCPDS card No. 38-1420; and (hkl)
are eight planes of (111), (220), (200), (311), (331), (420), (422)
and (511),
7. The coated tool according to claim 6, wherein the B1-type metal
compound film is columnar crystal.
8. The coated tool according to claim 6, wherein the B1-type metal
compound film is a metal compound film comprising a carbonitride of
Ti.
9. The coated tool according to claim 6, wherein an average film
thickness of the B1-type metal compound film is about 3 .mu.m to
about 20 .mu.m.
10. The coated tool according to claim 6, wherein there is an
undermost film between the substrate and the B1-type metal compound
film, and the undermost film is a metal compound film comprising
one or both of a nitride and carbonitride of Ti.
11. The coated tool according to claim 10, wherein an average film
thickness of the undermost film is about 0.1 .mu.m to about 1
.mu.m.
12. The coated tool according to claim 6, wherein there is an
adhesive film between the B1-type metal compound film and the
.alpha.-type aluminum oxide film, and the adhesive film comprises a
metal compound film comprising at least one of a carboxide,
nitroxide and carbonitroxide of Ti, and a carboxide, nitroxide and
carbonitroxide of Ti and Al.
13. The coated tool according to claim 12, wherein the adhesive
film is at least one selected from the group consisting of TiCO,
TiNO, TiCNO, TiAlCO, TiAlNO and TiAlCNO.
14. The coated tool according to claim 12, wherein the adhesive
film is a metal compound film comprising at least one of a
carboxide, nitroxide and carbonitroxide of Ti and Al.
15. The coated tool according to claim 12, wherein an average film
thickness of the adhesive film is about 0.3 .mu.m to about 2
.mu.m.
16. The coated tool according claim 1, wherein a surface of the
.alpha.-type aluminum oxide film is coated by an outer film, and
the outer film is a metal compound film comprising one or both of a
nitride and carbonitride of Ti.
17. The coated tool according to claim 16, wherein an average film
thickness of the outer film is about 0.1 .mu.m to about 2
.mu.m.
18. The coated tool according to claim 1, wherein the .alpha.-type
aluminum oxide film is formed by a chemical vapor deposition
method, and comprises a coated film having a film thickness of
about 0.1 to about 0.3 .mu.m formed under first step coating
conditions of a starting gas composition being AlCl.sub.3: 2.1 to
5.0 mol %, CO.sub.2: 2.5 to 4.0 mol %, HCl: 2.0 to 3.0 mol %,
H.sub.2: the remainder, at a temperature: 990 to 1000.degree. C.,
under a pressure: 60 to 80 hPa, and a coated film having a film
thickness of about 0.4 to about 9.9 .mu.m formed under second step
coating conditions of a starting gas composition being AlCl.sub.3:
2.1 to 5.0 mol %, CO.sub.2: 2.5 to 4.0 mol %, HCl: 2.0 to 3.0 mol
%, H.sub.2S: 0.28 to 0.45 mol %, H.sub.2: the remainder, at a
temperature: 990 to 1000.degree. C., under a pressure: 60 to 80
hPa.
Description
TECHNICAL FIELD
[0001] The present invention relates to a coated tool in which a
coating film is coated on the surface of a substrate, and to a
coated tool wherein at least one layer of the coating film is an
.alpha.-type aluminum oxide film.
BACKGROUND ART
[0002] In cutting, a coated tool in which a TiCN film or an
aluminum oxide film is coated on the surface of a cemented carbide
substrate has frequently been used. As the prior art of the coated
tool, there is a coated material at least partially coated with one
or more refractory layers of which at least one layer is a layer of
alumina, said alumina layer has a thickness of d=0.5-25 .mu.m, and
consisting of a single phase .alpha.-structure having a grain size
(S), said grain size (S) being 0.5 .mu.m<S<1 .mu.m for 0.5
.mu.<d<2.5 .mu.m, and said grain size (S) being 0.5
.mu.m<S<3 .mu.m for 2.5 .mu.m<d<25 .mu.m, said alumina
layer exhibits a texture coefficient (TC) greater than 1.3 for the
(012) growth direction of the equivalent crystallographic planes
defined by the following formula,
TC ( 012 ) = I ( 012 ) I 0 ( 012 ) { 1 n I ( hk 1 ) I 0 ( hk 1 ) }
- 1 , Formula ##EQU00001##
wherein I(hkl)=measured intensity of the (hkl) reflection,
I.sub.o(hkl)=standard intensity of the ASTM standard power pattern
diffraction data, n=number of reflections, and (hkl) reflection are
(012), (104), (110), (113), (024), (116) (for example, see Patent
Literature 1.). However, the coated material involves the problem
that it cannot show sufficient performances in a processing
requiring chipping resistance, in particular, in cutting of a
steel.
[0003] Also, there is a coated cemented carbide in which an
.alpha.-type aluminum oxide film showing TC(1,0,-1,4)=3.39,
TC(1,0,-1,2)=0.27 and TC(1,0,-1,4)/TC(1,0,-1,2)=12.6 is coated on
the surface of a cemented carbide to which a TiN film has been
coated (for example, see Non-Patent Literature 1, p. 417, Table
2.). However, this coated cemented carbide has extremely coarse
.alpha.-type aluminum oxide grains in the .alpha.-type aluminum
oxide film, so that there is a problem that it is inferior in wear
resistance at high temperature.
[0004] [Patent Literature 1] JP H06-316758A
[0005] [Non-Patent Literature 1] written by Chul-Soon Park, et al.,
"The effect of reaction condition on the crystallographic
orientation and surface morphology of chemical vapor deposited
Al2O3", Proceedings of the 4th European Conference on Chemical
Vapour Deposition, published by Philips Centre Manuf. Technol,
Eindoven, Netherlands, 1983, P.410-420
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0006] At the production site, there is a requirement that a
cutting time is shortened to improve productivity. Therefore,
cutting has been carried out under severe cutting conditions such
as high speed, high feeding, and heavy interrupted cutting. Under
such severe cutting conditions, too life of the conventional coated
tool becomes short, so that a coated tool having longer tool life
than before has been demanded. Also, in a wear resistant tool
represented by a die, increase in tool life has been demanded for
the purpose of improving productivity. The present invention has
been done in view of such a circumstance, and an object thereof is
to provide a coated tool excellent in adhesiveness of the film,
wear resistance, crater resistance and chipping resistance.
Means to Solve the Problems
[0007] The present inventor have researched on a coated tool in
which an .alpha.-type aluminum oxide film is coated, he has found
that when an average film thickness of the .alpha.-type aluminum
oxide film is controlled to about 0.5 to about 10 .mu.m, an average
grain size of the aluminum oxide grains in the .alpha.-type
aluminum oxide film to about 0.5 to about 1.5 .mu.m, and an
orientation of the .alpha.-type aluminum oxide film is controlled
so that TC.sub.A(104)/TC.sub.A(012) which is a ratio of a texture
coefficient TC.sub.A(104) of a (104) plane to a texture coefficient
TC.sub.A(012) of a (012) plane of the .alpha.-type aluminum oxide
film to 2.0 or more, then, adhesiveness of the film, wear
resistance, crater resistance and chipping resistance are improved.
Moreover, when a B1-type metal compound film is formed between the
substrate and the .alpha.-type aluminum oxide film, he obtained the
knowledge that when an average grain size of the B1-type metal
compound grains in the B1-type metal compound film is controlled to
about 0.15 to about 0.3 .mu.m, a maximum grain size of the B1-type
metal compound grains in the B1-type metal compound film is
controlled to about 1.0 .mu.m or less, and
TC.sub.B(422)/TC.sub.B(311) which is a ratio of a texture
coefficient TC.sub.B(422) of a (422) plane of the B1-type metal
compound film to a texture coefficient TC.sub.B(311) of a (311)
plane of the B1-type metal compound film is controlled to 1.5 or
higher, then, adhesiveness of the film, wear resistance, crater
resistance and chipping resistance are further improved.
Effects of the Invention
[0008] The coated tool of the present invention is excellent in
adhesiveness of the film, wear resistance, crater resistance and
chipping resistance. When the coated tool of the present invention
is used as a cutting tool or a wear resistant tool, tool life
thereof is increased.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 This is a drawing showing a cross-section shape of a
work piece material.
EMBODIMENTS TO CARRY OUT THE INVENTION
[0010] The substrate of the present invention is not particularly
limited, and a material having both of hardness and toughness is
preferred, which may be mentioned, for example, ceramics, alloy
steel, cemented carbide, cermet, etc. Among these, a cemented
carbide or cermet is preferred. The cemented carbide or cermet is
an alloy comprising a hard phase which comprises a carbide,
nitride, carbonitride, oxide, carboxide, nitroxide, carbonitroxide
and/or boride of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al and/or Si and
mutual solid solutions thereof, a binder phase mainly comprising
Co, Ni and/or Fe, and inevitable impurities. Among these, a
cemented carbide mainly comprising WC is further preferred since it
is excellent in toughness. To further have toughness to the
cemented carbide used as the substrate, it is preferred to provide
a .beta.-free layer comprising WC and a binder phase in which a
cubic crystal phase (.beta. phase) such as (W,Ti)C and (W,Ti,Ta)C
is disappeared at the neighbor of the surface of the cemented
carbide substrate with a thickness of about 5 to about 40 .mu.m
from the surface of the alloy to the depth direction.
[0011] It is preferred to apply to the surface of the substrate
machining represented by wet grinding, dry grinding and blasting,
or chemical processing represented by electrolytic polishing to
have preciseness of the tool shape to the substrate of the present
invention.
[0012] The coating of the present invention comprises the .alpha.
type aluminum oxide film of the present invention, or, comprises
one or more metal compound films comprising a carbide, nitride,
oxide, carbonitride, carboxide, nitroxide, carbonitroxide or boride
of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al or Si and a mutual solid
solutions thereof and the .alpha. type aluminum oxide film of the
present invention. On the surface of the substrate of the present
invention, the .alpha. type aluminum oxide film of the present
invention may be directly coated, but to improve wear resistance
and chipping resistance, a metal compound film is coated on the
surface of the substrate, and the .alpha. type aluminum oxide film
may be further coated on the surface of the metal compound film.
When the metal compound film is coated on the substrates such as a
cemented carbide, cermet, etc., a component(s) of the substrate
such as W, C, Co, Mo, Cr, V, etc., may sometimes be migrated from
the substrate to the metal compound film, but, even in this case,
the essential effects of the .alpha. type aluminum oxide film of
the present invention are not changed. Incidentally, it is
preferred to coat a metal compound film on the surface of the
.alpha. type aluminum oxide film according to the present invention
to distinguish the corner used for cutting by the difference at the
coated in difference such as a color, etc. The method for coating
the coating of the present invention to the substrate, there may be
mentioned a physical vapor deposition method or a chemical vapor
deposition method, etc.
[0013] The .alpha. type aluminum oxide film of the present
invention has an average film thickness of about 0.5 to about 10
.mu.m, an average grain size of about 0.5 to about 1.5 .mu.m, and a
texture coefficient TC.sub.A(012) of a (012) plane of the .alpha.
type aluminum oxide film shown by the following Numerical formula
1, and a texture coefficient TC.sub.A(104) of a (104) plane of the
.alpha. type aluminum oxide film shown by the following Numerical
formula 2 satisfy TC.sub.A(104)/TC.sub.A(012).gtoreq.2.0.
TC A ( 012 ) = I A ( 012 ) I A 0 ( 012 ) 1 8 [ I A ( 012 ) I A 0 (
012 ) + I A ( 104 ) I A 0 ( 104 ) + I A ( 110 ) I A 0 ( 110 ) + I A
( 113 ) I A 0 ( 113 ) + I A ( 024 ) I A 0 ( 024 ) + I A ( 116 ) I A
0 ( 116 ) + I A ( 124 ) I A 0 ( 124 ) + I A ( 030 ) I A 0 ( 030 ) ]
[ Numerical formula 1 ] ##EQU00002##
I.sub.A(hkl): X-ray diffraction intensity measured at the (hkl)
plane of the .alpha. type aluminum oxide film I.sub.A0(hk1):
Standard X-ray diffraction intensity of the (hkl) plane of the
.alpha. type aluminum oxide according to the JCPDS card No.
10-173
[0014] (hkl) are eight planes of (012), (104), (110), (113), (024),
(116), (124) and (030)
TC A ( 104 ) = I A ( 104 ) I A 0 ( 104 ) 1 8 [ I A ( 012 ) I A 0 (
012 ) + I A ( 104 ) I A 0 ( 104 ) + I A ( 110 ) I A 0 ( 110 ) + I A
( 113 ) I A 0 ( 113 ) + I A ( 024 ) I A 0 ( 024 ) + I A ( 116 ) I A
0 ( 116 ) + I A ( 124 ) I A 0 ( 124 ) + I A ( 030 ) I A 0 ( 030 ) ]
[ Numerical formula 2 ] ##EQU00003##
I.sub.A(hkl): X-ray diffraction intensity measured at the (hkl)
plane of the .alpha. type aluminum oxide film I.sub.A0(hkl):
Standard X-ray diffraction intensity of the (hkl) plane of the
.alpha. type aluminum oxide according to the JCPDS card No.
10-173
[0015] (hkl) is eight planes of (012), (104), (110), (113), (024),
(116), (124) and (030)
[0016] The .alpha. type aluminum oxide film of the present
invention has high strength of a grain boundary so that crack is
difficultly caused and adhesiveness to the ground is excellent.
Among these, TC.sub.A(104)/TC.sub.A(012) is more preferably 4.0 or
more, and TC.sub.A(104)/TC.sub.A(012) is further preferably 6.0 or
more. The .alpha. type aluminum oxide film of the present invention
has high strength of a grain boundary so that crack is difficultly
caused and adhesiveness to the ground, whereby dropping and
breakage of the crystal grains of the coating are reduced at the
time of cutting. Therefore, the coated tool in which the .alpha.
type aluminum oxide film of the present invention is coated thereon
is excellent in adhesiveness of the film, wear resistance, crater
resistance and chipping resistance.
[0017] The X-ray diffraction intensity of the .alpha. type aluminum
oxide film according to the present invention can be measured by
using the usual X-ray diffraction device equipped with a Cu bulb
according to the 2.theta./.theta. method. The X-ray diffraction
intensity in the present invention is made a peak height of the
X-ray diffraction chart obtained by the X-ray diffraction
measurement. In Table 1, a plane distance d (.ANG.) and a standard
X-ray diffraction intensity I.sub.A0 corresponding to the
respective crystal planes of the .alpha. type aluminum oxide
mentioned at No.10-173 of the JCPDS card are shown. In addition,
2.theta.(.degree.) of the respective crystal planes which can be
calculated from the wavelength 1.54056.ANG. of the K.alpha.1 line
of Cu and the plane distance d (.ANG.) of the respective crystal
planes is shown in Table 1.
TABLE-US-00001 TABLE 1 (hkl) (012) (104) (110) (113) (024) (116)
(124) (030) .alpha.-Al.sub.2O.sub.3 d (.ANG.) 3.479 2.552 2.379
2.085 1.740 1.601 1.546 1.374 2.theta. (.degree.) 25.58 35.14 37.78
43.36 52.55 57.52 66.55 68.20 I.sub.A0 75 90 40 100 45 80 30 50
[0018] When the measured range of 2.theta. is defined to be
20.degree. to 75.degree., an X-ray diffraction intensity I.sub.A
(hkl) from a (012) plane to a (030) plane of the .alpha. type
aluminum oxide film can be measured.
[0019] From the obtained X-ray diffraction intensity I.sub.A (hkl)
from the (012) plane to the (030) plane of the .alpha. type
aluminum oxide, a texture coefficient TC.sub.A(012) defined by the
Numerical formula 1, and the TC.sub.A(104) defined by the Numerical
formula 2 can be obtained.
[0020] The .alpha. type aluminum oxide film of the present
invention shows columnar crystal. The columnar crystal referred to
in the present invention means a crystal in which a grain diameter
measured at the direction perpendicular to the surface of the
substrate is longer than that measured at the direction parallel to
the surface of the substrate.
[0021] An average grain size of the .alpha. type aluminum oxide
grains in the .alpha. type aluminum oxide film of the present
invention can be obtained by taking a SEM photograph of the surface
structure of the .alpha. type aluminum oxide film to the direction
parallel to the substrate surface magnified to 10,000-fold by SEM
(scanning type electron microscope), drawing three or more lines on
the SEM photograph to the random directions, measuring distances
between crystal grain boundaries of the .alpha. type aluminum oxide
film crossed the lines, and making the average value an average
grain size of the .alpha. type aluminum oxide grains. When a metal
compound film is coated on the surface of the .alpha. type aluminum
oxide film of the present invention, the surface of the .alpha.
type aluminum oxide film can be preferably observed after removing
the same with fluoronitric acid, etc. If the average grain size of
the .alpha. type aluminum oxide grains in the a type aluminum oxide
film of the present invention is less than about 0.5 .mu.m,
fracture resistance is lowered, while if the average grain size of
the .alpha. type aluminum oxide grains in the .alpha. type aluminum
oxide film becomes large exceeding about 1.5 .mu.m, wear resistance
is lowered, so that the average grain size of the .alpha.-type
aluminum oxide grains in the .alpha. type aluminum oxide film is
set to about 0.5 to about 1.5 .mu.m. Also, if the average film
thickness of the .alpha. type aluminum oxide film according to the
present invention is less than about 0.5 .mu.m, wear resistance is
lowered, while if the average film thickness of the .alpha. type
aluminum oxide film becomes thick exceeding about 10 .mu.m,
fracture resistance is lowered, so that the average film thickness
of the .alpha. type aluminum oxide film is set to about 0.5 to
about 10 .mu.m.
[0022] The .alpha.-type aluminum oxide film of the present
invention may contain, as inevitable impurities, sulfur, a sulfide,
selenium and/or tellurium in an amount of 1 atomic % or less in
total based on the whole .alpha.-type aluminum oxide film of the
present invention.
[0023] When the B1-type metal compound film of the present
invention is coated between the substrate and the .alpha.-type
aluminum oxide film, adhesiveness between the .alpha.-type aluminum
oxide film and the substrate is markedly improved, and wear
resistance, crater resistance and chipping resistance are further
improved. When the B1-type metal compound film of the present
invention is at least one of a carbide, nitride and carbonitride of
an element of Groups 4 (Ti, Zr, Hf, etc.), 5 (V, Nb, Ta, etc.) and
6 (Cr, Mo, W, etc.) of the Periodic Table, and mutual solid
solutions thereof, it is excellent in wear resistance so that it is
more preferred. Among these, when it comprises a carbonitride of
Ti, it is further preferred.
[0024] An average grain size of the B1-type metal compound grains
in the B1-type metal compound film of the present invention is
about 0.15 to about 0.3 .mu.m, a maximum grain size of the B1-type
metal compound grains in the B1-type metal compound film is about
1.0 .mu.m or less, and a texture coefficient TC.sub.B(422) of a
(422) plane of the B1-type metal compound film shown by the
following Numerical formula 3, and a texture coefficient
TC.sub.B(311) of a (311) plane of the B1-type metal compound film
shown by the following Numerical formula 4 satisfy
TC.sub.B(422)/TC.sub.B(311).gtoreq.1.5.
TC B ( 422 ) = I B ( 422 ) I B 0 ( 422 ) 1 8 [ I B ( 111 ) I B 0 (
111 ) + I B ( 220 ) I B 0 ( 220 ) + I B ( 200 ) I B 0 ( 200 ) + I B
( 311 ) I B 0 ( 311 ) + I B ( 331 ) I B 0 ( 331 ) + I B ( 420 ) I B
0 ( 420 ) + I B ( 422 ) I B 0 ( 422 ) + I B ( 511 ) I B 0 ( 511 ) ]
[ Numerical formula 3 ] ##EQU00004##
I.sub.B(hkl): X-ray diffraction intensity measured at the (hkl)
plane of the B1-type metal compound film I.sub.B0(hkl): Average
value of standard X-ray diffraction intensity of the (hkl) plane of
TiC according to the JCPDS card No. 32-1383 and standard X-ray
diffraction intensity of the (hkl) plane of TiN according to the
JCPDS card No. 38-1420
[0025] (hkl) is eight planes of (111), (220), (200), (311), (331),
(420), (422) and (511)
TC B ( 311 ) = I B ( 311 ) I B 0 ( 311 ) 1 8 [ I B ( 111 ) I B 0 (
111 ) + I B ( 220 ) I B 0 ( 220 ) + I B ( 200 ) I B 0 ( 200 ) + I B
( 311 ) I B 0 ( 311 ) + I B ( 331 ) I B 0 ( 331 ) + I B ( 420 ) I B
0 ( 420 ) + I B ( 422 ) I B 0 ( 422 ) + I B ( 511 ) I B 0 ( 511 ) ]
[ Numerical formula 4 ] ##EQU00005##
I.sub.B(hkl): X-ray diffraction intensity measured at the (hkl)
plane of the B1-type metal compound film I.sub.B0(hkl): Average
value of standard X-ray diffraction intensity of the (hkl) plane of
TiC according to the JCPDS card No. 32-1383 and standard X-ray
diffraction intensity of the (hkl) plane of TiN according to the
JCPDS card No. 38-1420
[0026] (hkl) is eight planes of (111), (220), (200), (311), (331),
(420), (422) and (511)
[0027] X-ray diffraction intensity of the B1-type metal compound
film of the present invention can be measured by using an X-ray
diffraction device equipped with a Cu bulb according to the
2.theta./.theta. method. In Table 2, a plane distance d (.ANG.) and
standard X-ray diffraction intensity I.sub.0 corresponding to the
respective crystal planes of TiC shown in the JCPDS card No.
32-1383, a plane distance d (.ANG.) and standard X-ray diffraction
intensity I.sub.0 corresponding to the respective crystal planes of
TiN shown in the JCPDS card No. 38-1420, and an average value
I.sub.B0 of the standard X-ray diffraction intensity I.sub.o of TiC
and the standard X-ray diffraction intensity I.sub.o of TiN are
shown. Also, 2.theta. (.degree.) of the respective crystal planes
which can be obtained from a wavelength of 1.54056.ANG. of Cu
K.alpha. 1 line and a plane distance d (.ANG.) of the respective
crystal planes are shown in Table 2.
TABLE-US-00002 TABLE 2 (hkl) (111) (200) (220) (311) (420) (422)
(511) TiC d (.ANG.) 2.4990 2.1637 1.5302 1.3047 0.9677 0.8834
0.8327 2.theta. (.degree.) 35.906 41.710 60.448 72.369 105.497
121.372 135.348 I.sub.0 80.0 100.0 60.0 30.0 25.0 25.0 16.0 TiN d
(.ANG.) 2.4492 2.1207 1.4997 1.2789 0.9485 0.8658 0.8164 2.theta.
(.degree.) 36.662 42.596 61.812 74.068 108.607 125.672 141.312
I.sub.0 72.0 100.0 45.0 19.0 14.0 12.0 7.0 Average of I.sub.B0 76.0
100.0 52.5 24.5 19.5 18.5 11.5 TiC and TiN
[0028] When the measurement range of 2.theta. is made from
20.degree. to 145.degree., X-ray diffraction intensities of the
B1-type metal compound film from the (111) plane to the (511) plane
can be measured. There is a case where the X-ray diffraction peak
of the (311) plane of the B1-type metal compound film overlaps with
the X-ray diffraction peak of the WC(111) plane of the substrate.
Standard X-ray diffraction intensity I.sub.0 of the WC(111) plane
shown in the JCPDS card No. 25-1047 is 0.25-fold the standard X-ray
diffraction intensity I.sub.0 of the WC(101) plane, so that a value
deducted 0.25-fold X-ray diffraction intensity of the WC(101) plane
from the X-ray diffraction intensity at which the (311) plane of
the B1-type metal compound film and WC(111) plane are overlapped is
deemed to be the X-ray diffraction intensity I.sub.B(311) of the
(311) plane of the B1-type metal compound film. From the obtained
X-ray diffraction intensities I.sub.B(hkl) from the (111) plane to
the (511) plane of the B1-type metal compound, the texture
coefficient TC.sub.B(422) defined by the numerical formula 3 and
the TC.sub.B(311) defined by the numerical formula 4 can be
obtained.
[0029] The B1-type metal compound film of the present invention
shows a columnar crystal. The columnar crystal referred to in the
present invention means a crystal in which a grain diameter
measured at the direction perpendicular to the surface of the
substrate is longer than that measured at the direction parallel to
the surface of the substrate.
[0030] An average grain size of the B1-type metal compound film of
the present invention means an average grain size of the B1-type
metal compound grains in the B1-type metal compound film to the
direction parallel to the substrate surface, which is in the range
of within 1 pm from the interface between the .alpha.-type aluminum
oxide film and the B1-type metal compound film or the interface
between the adhesive film and the B1-type metal compound film to
the depth direction. If there is unevenness at the interface, it is
measured in the range within 1 .mu.m from the position nearest to
the substrate (at the valley portion). More specifically, an
average grain size of the B1-type metal compound film can be
measured from the lap surface of the B1-type metal compound film
appeared by removing the .alpha.-type aluminum oxide film or the
adhesive film according to the diamond-lap polishing of the coated
tool surface. Whether it is within 1 .mu.m from the interface
between the .alpha.-type aluminum oxide film and the B1-type metal
compound film or from the interface between the adhesive film and
the B1-type metal compound film or not can be confirmed by
cross-sectional observation. When the lap surface of the B1-type
metal compound film is subjected to corrosion treatment by a
fluoronitric acid, etc., a grain diameter of the B1-type metal
compound film can be easily measured. The lap surface of the
B1-type metal compound film is magnified to 10,000-fold by SEM and
a SEM photograph is taken, three or more lines are drawn on the SEM
photograph to random directions, distances between crystal grain
boundaries of the B1-type metal compound film which crossed the
lines are measured, the maximum value among these distances is made
a maximum grain size of the B1-type metal compound grains in the
B1-type metal compound film, and an average value of these
distances is made an average grain size of the B1-type metal
compound grains in the B1-type metal compound film. If an average
grain size of the B1-type metal compound grains in the B1-type
metal compound film of the present invention is less than about
0.15 .mu.m, fracture resistance tends to be lowered, while if an
average grain size of the B1-type metal compound grains in the
B1-type metal compound film becomes large exceeding about 0.3
.mu.m, wear resistance tends to be lowered. If a maximum grain size
of the B1-type metal compound grains in the B1-type metal compound
film of the present invention becomes large exceeding about 1.0
.mu.m, wear resistance tends to be lowered. Also, if an average
film thickness of the B1-type metal compound film of the present
invention is less than about 3 .mu.m, wear resistance tends to be
lowered, while if an average film thickness of the B1-type metal
compound film becomes thick exceeding about 20 .mu.m, fracture
resistance is lowered so that the average film thickness of the
B1-type metal compound film is preferably about 3 to about 20
.mu.m.
[0031] It is preferred when an undermost film comprising one or
more metallic compounds of a nitride and/or carbonitride of Ti is
present between the substrate and the B1-type type metal compound
film, since adhesiveness of the substrate and the coating is
heightened, and uniform columnar structure can be obtained in the
B1-type metal compound film, whereby, uniformity of the .alpha.
type aluminum oxide film structure and smoothness at the surface of
the .alpha. type aluminum oxide film is improved. More
specifically, there may be mentioned TiN and TiCN. If the average
film thickness of the undermost film of the present invention is
less than about 0.1 .mu.m, adhesiveness between the substrate and
the coating tends to be lowered, while if the average film
thickness of the undermost film becomes thick exceeding about 1
.mu.m, chipping resistance is lowered, so that the average film
thickness of the undermost film is preferably about 0.1 to about 1
.mu.m.
[0032] It is preferred when an adhesive film of a metallic compound
comprising at least one of a carboxide, nitroxide or carbonitroxide
of Ti, and a carboxide, nitroxide or carbonitroxide containing Ti
and Al is present between the B1-type metal compound film and the
.alpha.-type aluminum oxide film, since adhesiveness of the B1-type
metal compound film and the .alpha.-type aluminum oxide film is
improved. More specifically, there may be mentioned TiCO, TiNO,
TiCNO, TiAlCO, TiAlNO and TiAlCNO. Among these, the adhesive film
is more preferably a metallic compound comprising at least one of a
carboxide, nitroxide and carbonitroxide containing Ti and Al, among
these, the adhesive film is further preferably a carbonitroxide
containing Ti and Al. The carbonitroxide containing Ti and Al may
be specifically mentioned TiAlCNO. When TiAlCNO is to be prepared
by the chemical vapor deposition method, it can be obtained by
making the starting gas composition TiCl.sub.4: 3.0 to 5.0 mol %,
AlCl.sub.3: 1.0 to 2.0 mol %, CO: 0.4 to 1.0 mol %, N.sub.2: 30 to
40 mol %, and H.sub.2: reminder, and coating conditions at a
temperature: 975 to 1025.degree. C., and a pressure: 90 to 110 hPa.
Also, when the average film thickness of the adhesive film of the
present invention is less than about 0.3 .mu.m, adhesiveness
between the B1-type metal compound film and the .alpha.-type
aluminum oxide film tends to be lowered, while when the average
film thickness of the adhesive film becomes thick exceeding about 2
.mu.m, it tends to be broken from the fragile adhesive film, so
that the average film thickness of the adhesive film is preferably
about 0.3 to about 2 .mu.m.
[0033] It is preferred to provide at least one layer of an outer
film of a metallic compound comprising one or two of a nitride
and/or carbonitride of Ti on the surface of the .alpha. type
aluminum oxide film, since the corner used for cutting can be
easily identified by the difference in color, etc. More
specifically, there may be mentioned TiN and TiCN. Also, if an
average film thickness of the whole outer film of the present
invention is less than about 0.1 .mu.m, uniform color tone can be
hardly obtained, while if an average film thickness of the whole
outer film becomes thick exceeding about 2 .mu.m, welding
resistance tends to be lowered, so that the average film thickness
of the whole outer film is preferably about 0.1 to about 2
.mu.m.
[0034] The coated tool of the present invention can be prepared by
coating a coating on the surface of the substrate according to the
physical vapor deposition method or chemical vapor deposition
method. Among these, chemical vapor deposition method is preferred
since high adhesiveness between the substrate and the coating can
be obtained. When the chemical vapor deposition method is employed,
the .alpha.-type aluminum oxide film of the present invention can
be obtained by providing a coating with a film thickness of about
0.1 to about 0.3 .mu.m under the First step coating conditions
where a starting gas composition of AlCl.sub.3: 2.1 to 5.0 mol %,
CO.sub.2: 2.5 to 4.0 mol %, HCl: 2.0 to 3.0 mol %, and H.sub.2:
reminder, at a temperature: 990 to 1000.degree. C., and a pressure:
60 to 80 hPa, and then, providing a coating with a film thickness
of about 0.4 to about 9.9 .mu.m under the Second step coating
conditions where a starting gas composition of AlCl.sub.3: 2.1 to
5.0 mol %, CO.sub.2: 2.5 to 4.0 mol %, HCl: 2.0 to 3.0 mol %,
H.sub.2S: 0.28 to 0.45 mol % and H.sub.2: reminder, at a
temperature: 990 to 1000.degree. C., and a pressure: 60 to 80
hPa.
[0035] To obtain the .alpha.-type aluminum oxide film of the
present invention, it is coated under the conditions of First step
without adding H.sub.2S for 5 to 20 minutes, and thereafter, under
the conditions of Second step to which H.sub.2S is added. By not
adding H.sub.2S at the initial stage of the coating, core formation
of .alpha.-type aluminum oxide and film-forming speed are
optimized, whereby a ground of the .alpha.-type aluminum oxide film
which is uniform and dense can be obtained. In Second step, 0.28 to
0.45 mol % of H.sub.2S is added, so that a grain-growth speed of
the .alpha.-type aluminum oxide film is increased whereby an
.alpha.-type aluminum oxide film having uniform structure, high
adhesiveness and high strength can be obtained. Incidentally, when
H.sub.2S is added from the initial stage, core formation and
grain-growth speed of the .alpha.-type aluminum oxide are rapidly
increased, so that pores are formed at the interface of the
.alpha.-type aluminum oxide film and the adhesive film. These pores
cause lowering in adhesiveness and film strength of the
.alpha.-type aluminum oxide film.
[0036] In the coating conditions of the .alpha.-type aluminum oxide
film in First step and Second step, in the case of, for example, a
temperature: 1000.degree. C., and a pressure: 70 hPa, if CO.sub.2
contained in the starting gas becomes large exceeding 4.0 mol %,
TC.sub.A(104)/TC.sub.A(012) becomes less than 2.0 whereby cutting
properties are lowered. To the contrary, if CO.sub.2 contained in
the starting gas becomes less than 2.5 mol %, grain-growth speed of
the .alpha.-type aluminum oxide markedly lowered and film strength
is lowered, whereby adhesiveness of the film, wear resistance,
crater resistance and chipping resistance are lowered. For example,
in the case of a temperature: 1000.degree. C., and a pressure: 70
hPa, if AlCl.sub.3 contained in the starting gas becomes less than
2.1 mol %, TC.sub.A(104)/TC.sub.A(012) becomes less than 2.0
whereby cutting properties are lowered. To the contrary, if
AlCl.sub.3 contained in the starting gas becomes large exceeding
5.0 mol %, .alpha.-type aluminum oxide is formed in a gas phase so
that the .alpha.-type aluminum oxide film cannot be obtained.
[0037] In the case where the chemical vapor deposition method is
used, the B1-type metal compound film of the present invention can
be obtained by the coating conditions where a starting gas
composition of TiCl.sub.4: 10 to 15 mol %, CH.sub.3CN: 1 to 3 mol
%, N.sub.2: 0 to 20 mol %, and H.sub.2: reminder, at a temperature:
780 to 830.degree. C., and a pressure: 80 to 100 hPa. For example,
in the case of a temperature: 800.degree. C., and a pressure: 90
hPa, if CH.sub.3CN contained in the starting gas becomes less than
1.0 mol %, grain-growth speed of the B1-type metal compound film
markedly lowered, and film strength is lowered in some cases. If
CH.sub.3CN contained in the starting gas becomes large exceeding
3.0 mol %, X-ray diffraction peak intensity at the (311) plane of
the B1-type metal compound film becomes high in some cases, and
TC.sub.B(422)/TC.sub.B(311) becomes less than 1.5 in some cases, so
that an average grain size of the B1-type metal compound film
exceeds 0.3 .mu.m, and as a result, adhesiveness of the film, wear
resistance, crater resistance and chipping resistance are lowered
in some cases. For example, in the case of a temperature:
800.degree. C., and a pressure: 90 hPa, if TiCl.sub.4 contained in
the starting gas becomes less than 10 mol %,
TC.sub.B(422)/TC.sub.B(311) becomes less than 1.5, whereby
adhesiveness of the film, wear resistance, crater resistance and
chipping resistance are lowered in some cases. If TiCl.sub.4
contained in the starting gas becomes large exceeding 15.0 mol %,
an average grain size of the B1-type metal compound film becomes
less than 0.15 .mu.m, and the structure becomes granular crystals,
so that chipping resistance is markedly lowered in some cases.
Incidentally, the undermost film, adhesive film and outer film of
the present invention can be coated by the conventional physical
vapor deposition method or chemical vapor deposition method.
[0038] As the uses of the coated tool of the present invention,
there may be mentioned a cutting tool represented by an insert and
a wear resistant tool represented by a metal mold. When the coated
tool of the present invention is applied to the tool to which such
a high stress is applied, high effects can be obtained. When the
coated tool of the present invention is used as a cutting tool,
chipping at an edge portion to which a stress is particularly
concentrated hardly occurs and tool life is increased. When the
coated tool of the present invention is used as a wear resistant
tool, in particular, chipping at the edge portion is hardly caused
whereby tool life is increased.
Example 1
[0039] A mixed powder comprising 89% by weight of WC powder having
an average grain size of 4.5 .mu.m, 2% by weight of TiCN powder
having an average grain size of 1.5 .mu.m, 2% by weight of (Ta,Nb)C
powder having an average grain size of 1.5 .mu.m, and 7% by weight
of Co powder having an average grain size 1.5 .mu.m was sintered to
obtain a cemented carbide. The cemented carbide was worked to an
ISO standard CNMG120412-shaped insert and used as a substrate.
Incidentally, at the neighbor of the surface of the cemented
carbide substrate, a .beta.-free layer consisting of WC and Co is
formed. A thickness of the .beta.-free layer at a relief surface
was 15 .mu.m. To the substrate was provided a coating with the film
constitution shown in Table 3.
TABLE-US-00003 TABLE 3 Film constitution of coating films (film
thickness and composition) Second Fourth First layer layer layer
B1-type Third .alpha.-type Fifth Sixth Under- metal layer aluminum
layer layer most compound Adhesive oxide Outer Outer Total film
film film film film 1 film 2 film TiN TiCN TiAlCNO
.alpha.-Al.sub.2O.sub.3 TiCN TiN thickness Sample No. (.mu.m)
(.mu.m) (.mu.m) (.mu.m) (.mu.m) (.mu.m) (.mu.m) Present 0.2 8 0.8
5.5 0.5 0.5 15.5 products 1 to 8 Comparative 0.2 8 0.8 5.5 0.5 0.5
15.5 products 1, 2 and 4 Comparative 0.2 9 0.8 5.5 0.5 0.5 16.5
product 3 Comparative 1.2 8 0.8 5.5 0.5 0.5 16.5 product 5
[0040] The TiN film which is the first layer positioned at the
closest to the substrate side was coated under the coating
conditions where a starting gas composition is TiCl.sub.4: 9.0 mol
%, N.sub.2: 40 mol %, and H.sub.2: reminder, at temperature:
850.degree. C., and a pressure: 160 hPa. The TiCN film as the
second layer was coated under the coating conditions shown in Table
4.
TABLE-US-00004 TABLE 4 Coating conditions of TiCN film Tem- pera-
Pres- Starting gas composition (mol %) ture sure Sample No.
TiCl.sub.4 CH.sub.3CN C.sub.2H.sub.6 C.sub.2H.sub.4 H.sub.2 N.sub.2
(.degree. C.) (hpa) Present 10.8 1.3 -- -- 74.4 13.5 800 90 product
1 Present 10.8 1.3 -- -- 74.4 13.5 800 90 product 2 Present 10.8
1.3 -- -- 74.4 13.5 850 90 product 3 Present 10.8 1.3 -- -- 74.4
13.5 900 90 product 4 Present 10.8 1.3 -- -- 74.4 13.5 800 90
product 5 Present 10.7 1.7 -- -- 74.1 13.5 800 90 product 6 Present
10.7 1.7 -- -- 74.1 13.5 850 90 product 7 Present 10.8 1.3 -- --
74.4 13.5 900 90 product 8 Comparative 10.8 1.3 -- -- 74.4 13.5 800
90 product 1 Comparative 10.8 1.3 -- -- 74.4 13.5 800 90 product 2
Comparative 10.0 0.72 -- 2.7 73.28 13.3 860 90 product 3
Comparative 10.7 1.7 -- -- 74.1 13.5 850 90 product 4 Comparative
6.0 -- 0.4 -- 53.5 40.1 930 360 product 5
[0041] TiAlCNO film at the third layer was coated under the coating
conditions where a starting gas composition of TiCl.sub.4: 4.0 mol
%, AlCl.sub.3: 1.2 mol %, N.sub.2: 34 mol %, CO: 0.6 mol %, and
H.sub.2: reminder, at a temperature: 1000.degree. C., and a
pressure: 100 hPa.
[0042] With regard to the .alpha.-type Al.sub.2O.sub.3 film at the
fourth layer, in the case of Present products, coating was carried
out under coating conditions of First step shown in Table 5,
subsequently under coating conditions of Second step shown in Table
6.
TABLE-US-00005 TABLE 5 Coating conditions of First step of
.alpha.-Al.sub.2O.sub.3 film Tem- pera- Pres- Thick- Starting gas
composition (mol %) ture sure ness Sample No. AlCl.sub.3 CO.sub.2
HCl H.sub.2 H.sub.2S (.degree. C.) (hpa) (.mu.m) Present 2.3 3.6
2.0 92.1 -- 1000 70 0.3 product 1 Present 2.3 3.6 2.0 92.1 -- 1000
70 0.3 product 2 Present 2.3 3.6 2.0 92.1 -- 1000 70 0.3 product 3
Present 2.3 3.6 2.0 92.1 -- 1000 70 0.3 product 4 Present 2.2 3.6
2.1 92.1 -- 1000 70 0.3 product 5 Present 2.2 3.6 2.1 92.1 -- 1000
70 0.3 product 6 Present 2.2 3.6 2.1 92.1 -- 1000 70 0.3 product 7
Present 2.1 3.4 2.1 92.4 -- 1000 70 0.3 product 8
TABLE-US-00006 TABLE 6 Coating conditions of Second step of
.alpha.-Al.sub.2O.sub.3 film Tem- pera- Pres- Thick- Starting gas
composition (mol %) ture sure ness Sample No. AlCl.sub.3 CO.sub.2
HCl H.sub.2 H.sub.2S (.degree. C.) (hpa) (.mu.m) Present 2.3 3.6
2.0 91.8 0.3 1000 70 5.2 product 1 Present 2.3 3.6 2.0 91.8 0.3
1000 70 5.2 product 2 Present 2.3 3.6 2.0 91.8 0.3 1000 70 5.2
product 3 Present 2.3 3.6 2.0 91.8 0.3 1000 70 5.2 product 4
Present 2.2 3.6 2.1 91.82 0.28 1000 70 5.2 product 5 Present 2.2
3.6 2.1 91.82 0.28 1000 70 5.2 product 6 Present 2.2 3.6 2.1 91.82
0.28 1000 70 5.2 product 7 Present 2.1 3.4 2.1 92.12 0.28 1000 70
5.2 product 8
[0043] In the case of Comparative products, the .alpha.-type
Al.sub.2O.sub.3 film at the fourth layer was coated by the coating
conditions as mentioned in Table 7.
TABLE-US-00007 TABLE 7 Coating conditions of Second step of
.alpha.-Al.sub.2O.sub.3 film Tem- pera- Pres- Thick- Starting gas
composition (mol %) ture sure ness Sample No. AlCl.sub.3 CO.sub.2
HCl H.sub.2 H.sub.2S (.degree. C.) (hpa) (.mu.m) Comparative 2.3
3.6 2.0 91.8 0.3 1050 70 5.5 product 1 Comparative 1.9 3.6 2.0 92.2
0.3 1000 70 5.5 product 2 Comparative 2.0 7.4 1.5 88.83 0.27 1000
70 5.5 product 3 Comparative 1.8 3.6 2.0 92.3 0.3 1000 70 5.5
product 4 Comparative 1.7 3.6 2.2 92.22 0.28 1000 70 5.5 product
5
[0044] In both of Present products and Comparative products, TiCN
film at the fifth layer was coated under coating conditions where a
starting gas composition of TiCl.sub.4: 7.3 mol %, N.sub.2: 11.6
mol %, CH.sub.3CN: 1.2 mol %, and H.sub.2: reminder, a temperature:
1000.degree. C., and a pressure: 90 hPa. TiN film of the sixth
layer which is outermost layer was coated under coating conditions
where a starting gas composition of TiCl.sub.4: 9.0mol %, N.sub.2:
40 mol %, and H.sub.2: the reminder, at a temperature: 1000.degree.
C., and a pressure: 160 hPa.
[0045] With regard to the obtained samples, X-ray diffraction
measurements using CuK.alpha. line were carried out to obtain
TC.sub.A(104) and TC.sub.A(012). The value of
TC.sub.A(104)/TC.sub.A(012) was calculated, and the values are
shown in Table 8. The fifth layer and the sixth layer of the
samples of the present invention were removed by fluoronitric acid,
and a SEM photograph of the surface structure of the .alpha.-type
Al.sub.2O.sub.3 film was taken by magnifying to 10,000-fold with
SEM (scanning-type electron microscope). Three lines were drawn on
the SEM photograph to random directions, distances between crystal
grain boundaries of the .alpha.-type aluminum oxide film which
crossed the lines were measured, and the average value was made an
average grain size of the .alpha.-type aluminum oxide film. The
results are shown in Table 8. Also, it was confirmed from
cross-sectional observation that the .alpha.-type Al.sub.2O.sub.3
films which are the fourth layers of Present products are columnar
crystals, the .alpha.-type Al.sub.2O.sub.3 film which is the fourth
layer of Comparative product 1 is columnar crystal, and the
.alpha.-type Al.sub.2O.sub.3 films which are the fourth layers of
Comparative products 2 to 5 are massive.
TABLE-US-00008 TABLE 8 .alpha.-Al.sub.2O.sub.3 film Average grain
Sample No. TC.sub.A(104)/TC.sub.A(012) size (.mu.m) Present product
1 6.12 0.50 Present product 2 5.43 0.80 Present product 3 4.52 1.20
Present product 4 3.43 1.30 Present product 5 3.00 1.40 Present
product 6 3.00 1.40 Present product 7 3.00 1.40 Present product 8
2.05 1.50 Comparative product 1 4.00 4.00 Comparative product 2
1.82 1.40 Comparative product 3 0.20 0.80 Comparative product 4
0.90 1.40 Comparative product 5 1.50 2.50
[0046] With regard to the sample in which the fifth layer and the
sixth layer had been removed by a fluoronitric acid, X-ray
diffraction measurement was carried out using CuK.alpha.1 line
wherein the measurement range of 2.theta. was made 20.degree. to
145.degree., whereby TC.sub.B(422) of the second layer of TiCN film
and TC.sub.B(311) of the second layer of the same were obtained. At
this time, X-ray diffraction peak of the (311) plane of the TiCN
film at the second layer and X-ray diffraction peak of the WC(111)
plane of the substrate were overlapped, so that the value in which
0.25-fold of X-ray diffraction intensity of the WC(101) plane was
subtracted from the X-ray diffraction intensity of the (311) plane
of the TiCN film was deemed to be X-ray diffraction intensity of
the (311) plane of the TiCN film. A ratio of
TC.sub.B(422)/TC.sub.B(311) of TiCN film at the second layer was
shown in Table 9. Also, among the (111) plane to (511) plane of
TiCN film, the crystal plane showing the highest X-ray diffraction
intensity is shown in Table 9.
[0047] According to the diamond-lap polishing of the sample
surface, the lap surface of the TiCN film as the second layer which
was appeared by removing the third layer to the sixth layer was
treated with a fluoronitric acid, and a SEM photograph was taken by
magnifying to 10,000-fold by SEM. Three lines were drawn on the SEM
photograph to random directions, distances between crystal grain
boundaries of the TiCN film crossing the lines were measured, the
maximum value of these was made a maximum grain size of the TiCN
film, and an average value of these was made an average grain size
of the TiCN film. Incidentally, it was confirmed by cross-sectional
observation that the measured positions were within 1 .mu.m from
the interface between the TiAlCNO film of the third layer and the
TiCN film of the second layer to the depth direction. The average
grain size and the maximum grain size of the TiCN film were shown
in Table 9. Also, it was confirmed from cross-sectional observation
that the TiCN films of the second layers of Present products and
Comparative products were columnar crystals.
TABLE-US-00009 TABLE 9 TiCN film Maximum X- Average Maximum
TC.sub.B(422)/- ray diffraction grain size grain size Sample No.
TC.sub.B(311) intensity plane (.mu.m) (.mu.m) Present product 1
2.00 (422) 0.20 0.80 Present product 2 2.00 (422) 0.20 0.80 Present
product 3 0.50 (311) 0.40 0.80 Present product 4 0.20 (220) 0.70
1.84 Present product 5 2.00 (422) 0.25 0.80 Present product 6 1.50
(422) 0.30 1.00 Present product 7 0.50 (311) 0.40 0.80 Present
product 8 0.20 (220) 0.70 1.84 Comparative 2.00 (422) 0.20 0.80
product 1 Comparative 2.00 (422) 0.20 0.80 product 2 Comparative
0.20 (220) 0.40 2.40 product 3 Comparative 0.50 (311) 0.40 0.80
product 4 Comparative 0.20 (220) 0.25 2.40 product 5
[0048] By using the obtained samples, adhesiveness evaluation test
of the coating film and cutting test were carried out.
Adhesiveness Evaluation Test of the Coating Film
[0049] 5 specimens per one sample were prepared, adhesiveness
evaluation test was carried out wherein a Rockwell indenter is
pushed into the surface of the sample with an applied load of 60
kgf by using a Rockwell hardness tester and peeling of the coating
from the substrate was examined. The results are shown in Table
10.
TABLE-US-00010 TABLE 10 Adhesiveness evaluation test (n = 5) Number
of sample(s) coating of which peeled off from the Sample No.
substrate (number) Present product 1 0 Present product 2 0 Present
product 3 0 Present product 4 0 Present product 5 0 Present product
6 0 Present product 7 0 Present product 8 0 Comparative product 1 2
Comparative product 2 2 Comparative product 3 4 Comparative product
4 5 Comparative product 5 5
[0050] From Table 10, with regard to adhesiveness between the
substrate and the coated film, it can be understood that those of
Present products are superior to those of Comparative products.
[0051] As the cutting test, 5 specimens per one sample were
prepared, S55C (Hardness: H.sub.B255) having a cross-sectional
shape shown in FIG. 1 in which 50 mm.times.50 mm square hole had
been made along with the center axis of a cylinder having a
diameter 180 mm.times.a length 120 mm was used as a work piece
material, and edge face turning was carried out under the following
mentioned cutting conditions.
Cutting Conditions
[0052] Cutting speed: 220 m/min
[0053] Depth of cut: 2 mm
[0054] Feed rate: 0.35 mm/rev
[0055] Cutting form: Wet (using water-soluble emulsion)
[0056] Cutting time per 1 time: 15 min
[0057] Number of tested times: 5 times
[0058] After the cutting test, a size of the surface area wherein
the cemented carbide substrate is exposed to the surface at the
rake face was classified into large, medium and small, and the
number of these are shown in Table 11. Also, a number of samples in
which it was fractured by the progress of crater wear and a number
of samples which cause chipping at the cutting blade were examined,
and these results are shown in Table 11. Also, with regard to the
samples which were not fractured, flank wear was measured, and an
average value thereof is shown in Table 11.
TABLE-US-00011 TABLE 11 Cutting test results (n = number of tested
samples) Average of Number of Sample(s) flank wear of sample(s)
fractured sample(s) not Surface area of exposed causing by crater
fractured substrate (n = 5) chipping wear (n = number of Large
Medium Small [number] [number] measured Sample No. [number]
[number] [number] (n = 5) (n = 5) samples) Present 0 0 0 0 0 0.70
mm product 1 (n = 5) Present 0 0 0 0 0 0.80 mm product 2 (n = 5)
Present 0 0 1 0 0 0.90 mm product 3 (n = 5) Present 0 0 2 0 0 1.00
mm product 4 (n = 5) Present 0 0 3 0 0 1.05 mm product 5 (n = 5)
Present 0 0 4 0 0 1.10 mm product 6 (n = 5) Present 0 0 5 0 0 1.15
mm product 7 (n = 5) Present 0 0 5 0 0 1.20 mm product 8 (n = 5)
Comparative 4 1 0 0 1 1.50 mm product 1 (n = 4) Comparative 5 0 0 0
2 1.57 mm product 2 (n = 3) Comparative 5 0 0 4 2 1.57 mm product 3
(n = 3) Comparative 5 0 0 5 4 1.87 mm product 4 (n = 1) Comparative
5 0 0 5 5 -- product 5
[0059] As can be clearly seen from the results shown in Table 11,
it can be found that Present products are excellent in adhesiveness
of the film as compared with Comparative products so that the
substrate is hardly exposed, and chipping resistance, crater
resistance, fracture resistance and wear resistance are excellent.
Incidentally, Comparative products caused fracture and chipping,
and flank wear was 1.50 mm or more whereby they are judged to be
end of tool life. On the other hand, Present products did not cause
fracture and chipping, and flank wear was 1.20 mm or less, so that
it was possible to elongate the cutting time. That is, it can be
understood that Present products have longer tool life than those
of Comparative products.
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